The application of FTIR microspectroscopy in a non-invasive and non-destructive way to the study and conservation of mineralised excavated textiles

Abstract

The potential of Fourier Transform Infrared (FTIR) microspectroscopy, to inform the study and conservation of mineralised excavated textiles is discussed, highlighted by two case studies of 5th c. BCE finds. In both cases the textiles were funerary from pyre burials, used to wrap the remains of the incinerated bones of the deceased, and placed inside copper alloy urns, to be buried. FTIR spectra of the textile fibres were acquired by an FTIR microscope in reflectance mode. In regard to the two case studies, this was a non-invasive and non-destructive method, since it did not involve removal of material for sampling, as both finds were in a fragmentary condition, it did not apply any pressure, nor did it require pressing of the minute fragments used as samples. Past fibre analyses in case study A reported cultivated and wild silk, which had been used as evidence of the presence of silk in Classical Greece, while more recent studies, controversially pointed to either cellulosic or wool fibres. The unlimited application of FTIR microspectroscopy in reflectance mode due to its non-invasive/destructive nature, enhanced fibre identification but most importantly led to further analyses of specific fragments that revealed the find was suffering from active biodeterioration, subsequently treated. Case study B, where the textiles had been preserved folded, was a particularly unique find from its period, since one of the textiles present was bearing evidence of embroidery. Similarly, the extended application of FTIR microspectroscopy indicated good preservation of the organic matter within the fibres, informing thus the conservation decision-making process, which involved partial unfolding of the textiles, an action that revealed an additional decoration pattern, and minute fragments of the embroidery thread preserved.

Vibrational Spectroscopic Analyses and Imaging of the Early Middle Ages Hemp Bast Fibres Recovered from Lake Sediments

“…FT-IR microspectroscopical and chemometric analyses performed here provided information about the (bio)chemical composition and distribution of the individual compounds, such as different plant polysaccharides, in the ancient remains of hemp bast fibres [ 50 , 51 ]. Despite the numerous advantages of this method, data analysis and interpretation may be a very challenging task.…”

FTIR surface analysis for conservation

“…The surface-sensitive Attenuated Total Reflection Fourier Transform infra-red spectroscopy, ATR-FTIR is widely used in conservation. It has been used to characterise almost every material used in cultural heritage and its conservation [4][5][6] with many examples in the presentations of the thirteen Infra-red and Raman User Group conferences. The surface sensitivity of ATR-FTIR has more recently been used to follow the chemical degradation of rubber and amber [7,8].…”

The Bad and the Good—Microorganisms in Cultural Heritage Environments—An Update on Biodeterioration and Biotreatment Approaches

“…These methods enable the monitoring of microbial contamination and the state of artwork by spectra identification. They have already been employed for the analyses of pigment [ 72 ], textile fibers [ 73 , 74 ], mineral formation [ 52 ], and other natural organic substances such as oils, gums or glues [ 75 ]. One of the newest methodologies, allowing for early detection of microorganism activity is a technique using RGB-ITR laser scanner (Red Green Blue Imaging Topological Radar) [ 76 ].…”